Mars’ emitted energy and seasonal energy imbalance

What is it about?

The radiant energy budget of a planet is essential to understanding its surface and atmospheric processes. Here, we report the first systematic measurements of Mars’ emitted power, which are used to estimate the radiant energy budget of the red planet. Based on the observations from Mars Global Surveyor, Curiosity, and InSight, our measurements suggest that Mars’ global-average emitted power is 111.7±2.4 Wm-2. More importantly, our measurements reveal strong seasonal and diurnal variations of Mars’ emitted power. The strong seasonal variations further suggest an energy imbalance at the time scale of Mars’ seasons (e.g., ~ 15.3% of the emitted power in the Northern autumn for the Southern Hemisphere), which could play an important role in generating dust storms on Mars. We also find the 2001 global dust storm decreased the global-average emitted power by ~22% during daytime but increased the global-average emitted power by ~29% at nighttime. This suggests that global dust storms play a significant role in Mars’ radiant energy budget.

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Why is it important?

The radiant energy budget is a fundamental metric for planets. Based on the observations from multiple missions, we provide the first global picture of Mars’ emitted power. Furthermore, we estimate the radiant energy budget of Mars, which suggests that there are energy imbalances at the time scale of Mars’ seasons. Such energy imbalances provide a new perspective to understanding the generating mechanism of dust storms. Mars’ radiant energy budget is assumed to be balanced at all time scales in current models and theories, but our analyses show that the energy budget is not balanced at least at the time scale of Mars’ seasons. Therefore, current theories and models should be revisited with the newly revealed energy characteristics.

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